How do we know God's existence?

Scripture teaches that God's existence is acknowledged by all creation, as seen in Romans 1:20, which states, 'For the invisible things of Him from the creation of the world are clearly seen.' However, this knowledge is not saving knowledge. True understanding of God requires a heart change that only God can accomplish through regeneration. Believers are given a new heart that loves and reverences God, allowing them to know Him intimately—not just in a superficial way, as indicated in Romans 1:21, where people know God but fail to glorify Him as God.